> It seems basic, but has a temperature trigger been disproved? 

Several environmental cues associated with seasonal
changes, such as photoperiod, temperature, and nutritional
state, have been examined to determine if these trigger
seasonal changes in worker behavior and physiology and
overall colony behavior.

Temperature has also been investigated as a factor that
can trigger overwintering changes in bees. Moving a
summer colony to a cold room resulted in a significant
decrease in both biosynthesis rates and titers of JH in
foragers within 8 days. 

However, it was not explored
if this was a direct result of temperature and/or photoperiod
cues (these colonies were also kept in the dark) or an
indirect effect due to associated decreases in nutrition,
brood rearing, or restricted foraging activity. 

It is unlikely
that a rise in the ambient temperature serves as the
environmental cue to commence the brood rearing after
the winter break, since brood rearing stops in October and
November but restarts in the much colder December and January.

Döke, Mehmet Ali. Current Opinion in Insect Science 2015, 10:185–193 

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